1. Field of the Invention
This invention relates to a remote control commander for an electronic appliance, such as a television set, and more particularly to an optical motion sensing remote control system for an electronic appliance.
2. Related Art
An IR (Infra Red) remote controller is a common means to control a TV from a distance. However, existing remote controllers have some drawbacks. They are easy to lose. The user often mistakes a VCR controller for the TV controller. In fact, a lot of people have a great xe2x80x9cremote controller collectionxe2x80x9d. Also one has to learn which button is where on the controller. Remote controllers require batteries which have to be replaced periodically. If a TV could have a camera vision and read the user""s gestures, no remote controller would be necessary. However, it is not easy for a TV to distinguish gestures from other moves in its camera view. One would not want the channel to change each time the user got up to fetch a snack from the kitchen, for example.
The above and other problems of prior art remote control system for electronic device are overcome by an remote control system for electronic device according to the present invention which includes a display screen (which may be part of the device, e.g. a TV screen) for displaying icons representing possible operations of the electronic device, and a motion detector circuit for detecting a motion within a field of view of the motion detector circuit. The motion detector circuit detects a predetermined motion of a moving object within the field of view as an indication that a remote control operation is to be started and, thereafter, tracks the movement of the object. The motion detector circuit outputs a cursor control signal representative of the motion of the object. A control circuit, connected to the display screen, the electronic device, and the motion detector circuit and supplied with the cursor control signal, controls the display screen to display a movable visual indicator, e.g. a cursor, whose own motion tracks the movement of the moving object and the electronic device to perform operations corresponding to the icons selected by the user using the visual indicator.
In a preferred embodiment, the motion detector circuit detects the selection of an icon by the user by detecting a predetermined motion pattern of the object when the visual indicator is coincident on the display screen with a particular icon. For example, the motion detector circuit detects the selection of an icon by the user by detecting a cessation of movement of the object for a predetermined period of time after the visual indicator is coincident on the display screen with a particular icon. The detected object can be, for example, the user""s hand. The predetermined motion can be a circular hand movement.
In the preferred embodiment, the motion detector circuit includes a video camera and calculates a motion vector of each macro block between two adjacent video frames in a video output signal from the video camera. Each video frame includes a plurality of blocks, each containing vectors representative of detected motion of the object. Neighbor vectors with almost the same direction are grouped as one region. For each frame, the motion detector circuit, in determining whether to track an object, checks each region to determine if that region satisfies the conditions (a) that the vector made one rotation clockwise or counterclockwise and (b) the region returned to the start position where it used to be and locks onto that region if conditions (a) and (b) are both satisfied.
In order that the same general length of hand movement will control the visual indicator to move a consistent corresponding length of movement, the control circuit includes an automatic cursor sensitivity adjustment feature which automatically scales the extremes of the movement of the visual indicator to the extremes of the predetermined hand motion so that, for example, the same diagonal motion of the user""s hand will cause the visual indicator to move just across the diagonal of the display screen regardless of whether the user is close to the motion detector circuit or far away.
A remote controlling method for an electronic device according to the invention includes the steps of visually displaying on a display screen such as a TV screen, icons representing possible operations of the electronic device (e.g. a TV), detecting a motion within a field of view, including detecting a first predetermined motion of a moving object within the field of view as an indication that a remote control operation is to be started and, thereafter, tracking the movement of the object an outputting a cursor control signal representative of the motion of the object. In response to the control signal, controlling the display screen to display a movable visual indicator, e.g. a cursor, whose movement tracks the movement of the moving object and further controlling the electronic device to perform operations corresponding to the icons selected by the user using the visual indicator. The first predetermined motion can be any hand movement, such as a circular movement or a diagonal hand movement, for example.
The step of detecting the selection of an icon by the user includes detecting a second predetermined motion pattern of the object when the visual indicator is coincident on the display screen with a particular icon. For example, the predetermined motion pattern could be a cessation of movement of the object for a predetermined period of time after the visual indicator is coincident on the display screen with the particular icon.
The motion detecting step uses a video camera in the preferred embodiment and includes calculating a motion vector of each macro block between two adjacent video frames in a video output signal from the video camera. Each video frame includes a plurality of blocks each containing vectors representative of detected motion of the object, wherein neighbor vectors with almost the same direction are grouped as one region. For each frame, the determination of whether to track an object is made by checking each region to determine if that region satisfies the conditions (a) that the vector made one rotation clockwise or counterclockwise and (b) the region returned to the start position where it used to be. That region is locked onto if conditions (a) and (b) are both satisfied.
In order that the same general length of hand movement will control the visual indicator to move a consistent corresponding length of movement, the remote controlling method according to the invention further includes a step of automatically adjusting the sensitivity of the visual indicator by the steps of automatically scaling the extremes of the movement of the visual indicator to the extremes of the predetermined hand motion so that, for example, the same diagonal motion of the user""s hand will cause the visual indicator to move just across the diagonal of the display screen regardless of whether the user is close to the motion detector circuit or far away.
The foregoing and other objectives, features and advantages of the invention will be more readily understood upon consideration of the following detailed description of certain preferred embodiments of the invention, taken in conjunction with the accompanying drawings.